Shingled Solar Cell Module with Conductive Bonding
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Solution Overview
Problem
Conventional solar cell modules face inefficiencies due to hot spots and thermal damage, particularly in reverse biased cells, which can lead to reduced performance and reliability.
Innovation Solution
The solution involves arranging solar cells in a shingled manner with overlapping long sides and conductive bonding to form super cells, which are encapsulated in a thermoplastic olefin polymer between glass sheets, enhancing heat conduction and preventing hot spots, and using flexible electrical interconnects to accommodate thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solar cells are arranged in conventional non-overlapping configuration, then manufacturing is simpler, but hot spots and thermal damage occur reducing reliability
Solution Approach 1:
The solar cell array is segmented into individual solar cells that are electrically connected in series through conductive adhesive bonds at overlapping regions. Each solar cell operates independently but contributes to the overall series string, allowing localized thermal management and preventing hot spots from affecting the entire module.
Solution Approach 2:
A conductive adhesive serves as an intermediary element between adjacent solar cells, providing both electrical connection for series configuration and thermal conduction pathway. This intermediary component enables heat dissipation from high-current-density regions while maintaining electrical continuity.
2Reliability
If solar cells are arranged in shingled overlapping configuration with conductive bonding, then hot spots are reduced improving reliability, but manufacturing complexity increases
Solution Approach 1:
The electrical connection function and thermal management function are merged into a single conductive adhesive bonding layer. This multi-functional approach eliminates the need for separate electrical interconnectors and simplifies the manufacturing process while maintaining reliability benefits.
Solution Approach 2:
The solar cells are configured in series connection with increased breakdown voltage (greater than 10 volts per cell, with N≥25 cells), changing the electrical parameters to operate at higher voltages. This parameter change reduces current density and associated thermal issues while maintaining power output.
3Power
If solar cells are connected in series with N≥25 cells having breakdown voltage greater than 10 volts, then high voltage output is achieved, but thermal management becomes more critical
Solution Approach 1:
Flexible electrical interconnects are used to accommodate thermal expansion and contraction of solar cells during temperature cycling. The flexibility of these interconnects prevents mechanical failure from thermal stress while maintaining electrical connection integrity.
Solution Approach 2:
The module employs composite construction with thermoplastic olefin polymer encapsulation between glass sheets, creating a multi-layer composite structure. This composite design provides thermal management, mechanical protection, and electrical isolation while allowing the series-connected solar cells to operate at high voltages with improved thermal stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration improves the reliability and efficiency of solar cell modules by reducing hot spots and thermal damage, ensuring safe and reliable operation while maintaining high direct current voltage output.
Implementation Method 1
enhancing heat conduction and preventing hot spots
Implementation Method 2
using flexible electrical interconnects to accommodate thermal expansion
Data Source
Figure 1~2A
Figure 2B~2G
Figure 2D~2E
AI summary
A high efficiency configuration for a solar cell module comprises solar cells conductively bonded to each other in a shingled manner to form super cells, which may be arranged to efficiently use the area of the solar module, reduce series resistance, and increase module efficiency. The front surface metallization patterns on the solar cells may be configured to enable single step stencil printing, which is facilitated by the overlapping configuration of the solar cells in the super cells. A solar photovoltaic system may comprise two or more such high voltage solar cell modules electrically connected in parallel with each other and to an inverter. Solar cell cleaving tools and solar cell cleaving methods apply a vacuum between bottom surfaces of a solar cell wafer and a curved supporting surface to flex the solar cell wafer against the curved supporting surface and thereby cleave the solar cell wafer along one or more previously prepared scribe lines to provide a plurality of solar cells. An advantage of these cleaving tools and cleaving methods is that they need not require physical contact with the upper surfaces of the solar cell wafer. Solar cells are manufactured with reduced carrier recombination losses at edges of the solar cell, e.g., without cleaved edges that promote carrier recombination. The solar cells may have narrow rectangular geometries and may be advantageously employed in shingled (overlapping) arrangements to form super cells.